Toshihiro Nikai, secretary-general of Japan's ruling Liberal Democratic Party, did not discuss the matter with Xi directly during the pair's 17-minute talk in Beijing on Tuesday, which was concerned mainly with the possibility of Chinese leaders including Xi visiting Japan and Prime Minister Shinzo Abe visiting China. But Nikai told a news conference afterward that he would discuss the matter thoroughly with Abe when he returns home.

Pulling Japan into the organization would be a significant win for China, and was likely on Xi's mind as he received the Japanese lawmaker. Nikai had told his traveling press pool Monday that the government will see "how quickly we can reach a decision" on AIIB membership. Japan and the U.S. steered clear of the organization when it set sail in 2015.

Abe himself said in an interview Monday with Broadcast Satellite Japan and CNBC of the U.S. that Tokyo will discuss the matter carefully with Washington. "First of all, there remains the issue of whether impartial governance can be established," he said. "Secondly, there is the issue of the sustainability of debt servicing on the part of the borrowing countries and whether the societal and environmental impact are duly considered."

Neither Finance Minister Taro Aso nor Chief Cabinet Secretary Yoshihide Suga went into detail regarding the AIIB when speaking to the press Tuesday, saying only that no changes have yet been made to Japanese policy.

Nikai was in Beijing as part of Japan's delegation to the Belt and Road Forum for International Cooperation promoting China's massive infrastructure initiative. Takaya Imai, Abe's executive secretary, was in attendance as well, though not Economy, Trade and Industry Minister Hiroshige Seko, as Beijing had hoped. Nikai called the event a "great success" in an interview with Chinese state television.

Mutual benefit

The lawmaker met with Xi the day after the forum ended, delivering a letter from Abe to the president that called for reciprocal visits. Xi said he would consider sending high-level officials to Japan, and called on Tokyo to join Beijing in working toward friendly ties.

Tokyo sees economic forums and future talks as chances to improve relations with Beijing more broadly. This is particularly important as North Korea's nuclear weapons and missile programs progress, given Beijing's heavy influence on Pyongyang. "Japan and China are united in their intent to denuclearize the North," a Japanese foreign ministry official said.

U.S. President Donald Trump has also helped nudge the countries closer together. While the U.S. and Japan remain strong allies, the transactional nature of Trump's diplomacy makes it tough to predict how he will approach that relationship in the future. "As the U.S. and China draw closer, Japan fears being left out," an official accompanying Nikai said. Meanwhile, building ties to a U.S. ally is a strong strategic move on China's part, particularly at a time when stability in foreign policy is a chief concern.

China's Communist Party will choose new leadership this autumn at the twice-a-decade National Congress, where Xi will begin his second term as general secretary. Avoiding sticky foreign policy questions will allow the president to focus more completely on shaping staff appointments as he sees fit. Meanwhile, cooperation from Japanese companies could help invigorate China's slowing economy.

But there is no guarantee these efforts to improve ties will persist. Chinese state news outlet Xinhua did not discuss the prospect of Xi visiting Japan or Abe coming to China in coverage of the president's meeting with Nikai. Elements in the Communist Party opposing Xi's policies could also rustle up anti-Japanese sentiment to gather support as the National Congress draws near.